1. Field of the Invention
This invention relates to a vehicle steering wheel and, more particularly, to a steering wheel of the center horn type which actuates a horn upon depression of a horn pad covering above a boss section.
2. Description of the Prior Art
A conventional steering wheel of the center horn type is configured as shown in FIGS. 1 through 3 (see Japanese Utility Model Application Laid-Open No. 60-182256).
In the conventional steering wheel WO, a horn pad 1, which covers above a boss section B and actuates a horn upon depression, has a plurality of hook legs 2 provided at marginal portions on the back side thereof. This horn pad 1 is attached to a steering wheel body 4 by locking these hook legs 2 in latch portions 5 of the steering wheel body 4.
Each hook leg 2 has an enlarged head portion 2b provided at the distal end of a shaft portion 2a thereof, this head portion 2b having a gap 2c formed in the axial direction thereof so that the diameter of the head portion can be reduced.
Each latch portion 5 is substantially cylindrical, whose inner diameter is tapered to define a narrow portion 5a.
The horn pad 1 is assembled to the steering wheel body 4 by inserting each hook leg 2 in the corresponding latch portion 5 such that the upper side of each head portion 2b is locked by the lower side of the corresponding narrow portion 5a.
In the assembled state, the horn pad 1 is urged upward from the steering wheel body 4, because projections 3 provided at marginal portions on the back side of the horn pad 1 are in abutment on corresponding end portions of movable contact plates 6 made of flat springs which are disposed in front and rear marginal portions of the steering wheel WO and laterally extended.
Specifically, each movable contact plate 6, together with a mating stationary contact plate 7 disposed below the plate 6, composes a horn switch unit H with an insulating material 8 interposed therebetween. Each contact plate 6 is connected to the positive side of a horn actuating circuit, whereas each stationary contact plate 7 is connected to the negative side of the horn actuating circuit.
In the foregoing steering wheel WO, when the horn pad 1 is depressed, the projections 3 descend in opposition to the urging force of the movable contact plates 6 so that contact points 6a of the movable contact plates 6 are brought into contact with contact points 7a of the stationary contact plates 7; as a result, the horn is actuated.
According to the conventional steering wheel WO of the center horn type, when a central portion of the horn pad 1 is depressed, the whole horn pad 1 descends substantially uniformly.
However, when the horn pad 1 is depressed at its front/rear or left/right marginal portion, because of the presence of the clearances between the shaft portions 2a and the narrow portions 5a that are incorporated to provide slidability between them, one margin, on the side of a depressed portion, of the horn pad 1 sinks most so that the horn pad 1 takes an oblique position. Accordingly, the circumference of the horn pad 1 tends to interfere with a lower cover 9 surrounding the horn pad 1 or with a coating layer 10 of a spoke section S on the side of the steering wheel body 4 (such interference will not occur when the whole horn pad 1 descends substantially uniformly).
To avoid the interference of the horn pad 1 with the surrounding components at the time of depression, the conventional steering wheel WO of the center horn type is required to involve a comparatively wide clearance between the horn pad 1 and the surrounding steering wheel body 4, this causing a degradation of the appearance of the steering wheel WO.